In the prior art, the following image processing device and method is used to detect the location of the feature of interest in the object image.
As a first step, reference pattern data representing a reference pattern are obtained by imaging a reference model and recording it. Then, object image data representing an object image are obtained by imaging an object image by scanning, pixel by pixel, using a window large enough to contain the reference pattern. At each location of the window, a coincidence calculation is made to determine the degree of coincidence between the reference pattern data and the object image data. A location of the window where the object image data shows the highest coincidence with the reference pattern data is chosen as the location of the feature of interest in the object image.
Since the prior art image location detecting device must calculate the degree of coincidence between the reference pattern data and the object image data while scanning pixel by pixel, a large number of calculations are required at each scanning position, with the result that it is impossible to determine the location of the feature of interest at high speed.
Also, because it is calculated in pixels, the location of the feature of interest cannot be determined more precisely than in units corresponding to the size of a pixel.